Automatic telephone system



Nov. 10, 1925. 1,560,822

E. JACOBSEN AUTOMATIC TELEPHONE SYSTEM Filed Feb. 11, 1918 2Sheets-Sheet 1 [mrsnfur Emmi Jcmbsen Nov. 10, 1925. 1,560,822

E. JACOBSEN AUTOMATIC TELEPHONE SYSTEM Filed Feb. 11, 1918 2Sheets-Sheet 2 InuenZnr Emzl acubssn HZZurney Patented Nov. 10, 1925.

Emir. fimcosssu', cr'cgrciteo, rumors, v em. eee ee x wos Ass'grmonmoiiu'rcmg'rrq snge rnre coine swear AUTOMATIC TELEPHONE SYSTEM.

i n unian n u'remryimnmt-sseuenm zlwa,

and. a resident .of Chicago, Cpok-- Qounty,; and State of lllinois haveinventedcertein. new itnd useful: Improvements .in: Automatic TelephoneSystems; of-which thentollowi-ng is .-specification.-; lity inventionrelates in general :to impmuedrcircuits andnapparatus ffor .,use -inautomatic :telephone. systems or in Semi-autoiuuiticftelephone-systems}n whichrautbmatic switt'l-ies are controlled: by::asubscriber or operator to establish connections.

izMore specifically imyninvention relates-$01 imp'rovedswitches' and:apparatus ion usenin thus-type of system whevefpertynor. olystationalinesiare z emplo'yedJandrwhere: itferent f-requenciesare conneotdrto a.party line to signl' the various stationsthere-on.

"In-'21 part line systeiningvhielr-it is desired: to '.!n'21l c:'tl1(.pirrty dines -of2 a- -,-system accessible to local and lng--distance--.calls it has heretofore been: the common. practice to usethe well lznowui'freqhency selecting: coir nectar switch which responclsifirstirto one digit of the called number-t electa -group of'liues;then to a second digit to connect with'tl'ic desired line in the group.and-last :2 third digit which is used ilo-operate an :u -iilizirrfrequency selecting-switch to -f-ler-t the desired frequency.

In a great number of systems it is required that. when an operatorseizes a connector by m rn? c her-toll selector switch and findsied'lincbusy, she may leave the eonuezt :u-set up until the line goesidle, when the corner-tor switch will cut in and 'ring. New inattempting to use a. switchin which the 12*. digit is used to select thefrequency it was found that very often the operator, after the linehecmue'i'dle, either neglected to (fill the last digit to selectEt/hefrequency '11 -e had b the-t time forgotten'the ireucz' which was neededfor the desired tat on.

nwug the objects of any invention, thereany. s the provision, in aswitch which is T for he th local and long distance con nee ens; ofmeans whereby the first digit-dcmeal to the connector selects thefrequent desired "and the last two digits select the ca led lineterminals. In this mannerthe difficulties above p'einted outwill-be'ovwgquenoytmillgelreedm-hevehem-eelcdcdnnd I yzimthercopezatienir quimd when the-dine: become (idle: ejiore he rswithitc ut m t cal y enneqtt-the sel cte ingingcurneuttdthe calledtline; 2.11 th dr wings 21: have. --,s iw m en-v operawrzs-mllg electon V.tFiigtihnhsving we atoll rircqueneymelecting-zc une wr H (Eggfllwvhmh-iw re access wait-.hlil eh y-ot party hues sum amtethet in whichtlie-z-suhstation-Ai is. ne oft-, heivste i nsz I haveshowmthereubstatiqn A-ms busyin :a. locel. canneot on ."haviingatseindiviqlual= Lin swlmll'ig meotednteipatnupkdine. E'lhc connectpnlilsmlso multi lled mto the. bank dfea plurahtyuofilocahselectflrs tnohswm) whichimaynbeiofi mnyiwc l k wn! two Wire type.Y.Associetedawith-thaieoniiectgen H i uxil ary: frequency selecting fiii flltlewl lflh isrusedto Fsfilectzl lhe, des ed frequ ncy wot ringinicurrezit. 4 i d willm rviipoin ul morein-detatil the methodiotrcp natio.i-lrvclvedi-whem an op rator uatte nptsgtb estab ishes. co ection withthe Line-o substatio A-wh-fleseidl-ine is .busy ;iand..elso the resultswhich occur when-said line becomesvidlen.

The bperatonfi-rst inserts thefialling plug of -;her cord: cii'cuitiinto the .-j ack 'X of the selector E; thereby-closing, at the springsilthe operating-circuit from her eordeireuit through the springs 3 end.4t,- and; relay ',5-.to battery. "The relay 5 will immediatel :energizeover: this-yci-muit irom ground through theusual calling .deviee rinithe; sleeveconduotor oft-he cord circiiitgav-nd rupon energizing,;closes a circuit for the slow. relay -6 from ground-through-vsprings 8and 9,,and relay 6 to battery. The relay {M1150 closes ahighresistanceshunt circuitiabout the condenser 10.wl1ich :isconnected-between a pair of the windings -of-- the; repeating coil, saidcircuit extending tnom the upper side of condenserdO, springs 11, lowerwindingof relay 12,-and resistance 13- tothe lowerside of the condenser.:Theclosureof-this shunt circuit however haszno effect at=t11is time-asthe talking circuit is stilliopen at the springs 14 and 15. Theenergizetionof-theslowrelay 6 over the previously traced circuitsu-pplies -a =ground-to the supervisory circuit through-springs 19 and20 to light thetbusy huup 16 end otliers which may be .multi'pled Nowwhen the operators"calling devioe is operated for the first digit of thecalled number, the"'circu1t of the line relay is thereby interrupted "acorresponding "'num-' berof times; Each time the relay 5 deenergizes', it closes a circuit from-group through springs Band-21, springs 61',springs 18, re-

" lay 16, and vertical magnet-[17 to'battery.

The'.vertical magnetyl? operates in response to this "series of impulsesto 'lift the wipers" 22, 23, 'and '24-"opposite some levelof the banks"to which connector switches; having access to a'desired' g'roup oflines, are connected; ''--Although the circuits of relays 6 and 16 areinterruptedi momentarily at each operation of relay -5',-both-avill='remain ener gized during tran smi sion ofsuch impulsesand, afterthe impilses c ease andrelay '5 comes to rest energized; the relay 16 will fallback and relay 6 will remain energized." As soon as the vertical magnetoperates,to raise the shaft and wiper's one step',-the off-normalsprings 25"a'nd 26'closefi The springs 26 close the circuit of releasemagnet 27at onepoint and the springs 25 close a point in the circuit ofthe rotary interrupter relay 28. The circuit of release magnet 27 ismaintained open at' the back contact of relay '6; The relay 28, however,energizes as soon as the springs 25 close, over a circuit extendin fromground through springs 19 and 20 o relay 6, springs 29 and 30 of relay16, springs 25, and'relay 28 to battery. The relay 28, upon energizing,closes a locking circuit for itself at the springs 31 extending fromground't-hrough springs 7, springs 31, interrupter springs 32 of rotarymagnet 33, springs 25, and relay 28 to battery, and also closes onepoint in the circuit of the rotary magnet 33 at springs 34. Now afterthe impulses for the first digit cease and the relay 16 (leenergizes, acircuit is closed for the rotary magnet extending from ground throughsprings 19 and 20, springs 29 and 35, springs 34, and magnet 33 tobattery. The rotary magnet 33 therefore operates to step the wipers 22,23 and 24 one step onto the first set of contacts in the bank levelbefore which it stands. Another result of the operation of the rotarymagnet is to open the locking circuit of the relay 28 at springs 32. Therelay 28 will therefore deenergize and open the circuit ofthe rotarymagnet at springs 34 and also open a contact in its own locking circuitat springs 31. As soon as the springs 34 open, the rotary magnet willdeenergize and ing now that a ground potential will be again closesprings 32. Assumthe trunk line selected is busy,

found on the pri- 32 come. into cgntact, a new.c1rcu1t will be closedfor springs 32,

the relay 28 extending from {-1 groundgoverthe-wiper 24, springs 36 and37,

springs 25, and relay 28 to battery.-- ";I,he: *relay '28 will againoperate to close the circuit of magnet 33 and its own locking circuit,the said magnet operating to step the w alternate operation ipers to thenext contact. This of the relay 28 and rotary magnet 33 continues untilan idle trunk line is reached, at

which time no ground will be found upon the private contact and therelay28 will therefore remain deenergized after the springs 32 areclosed. It may be here noted that. during the energization of the relay16 the wipers, the relay with the relay 28, is cuited, first, by the 19,20, 29, and 30 an groundon the private wiper. tioned short circuitextends and also during the rotation of 38, although in seriesmaintained short cirround through springs during rotation by the Thelast menfrom ground on wiper 24, springs'36 and 37 relay 38, springs 20and 19 to ground. Now, however, when an idle trunk is reached, thisshort circuit is removed and the relay 38 which is of high resistanceenergizes in series with relay 28. The circuit for energizlng this relayextends from ground through the springs 19 and 20,

relay 38, springs 32, springs 25, and relay 28 to battery.

The relay 28 does not energize over this circuit on account of the highresistance of the winding of relay 38. The

relay 38, upon energizing, extends the talking circuit from the windings39 and 40 of the repeating coil to the wipers 22 and 23,

and also prepares a through the springs 36 be supplied ahead as willocking circuit for itself and 41 which will with ground from the switch1 be pointed out. Another result of the energization of relay 38 is toremove ground 28 by opening from the springs 31 of relay the springs 7,and to open the circuit of the vertical magnet 17 at the springs 61 toprevent further operation thereof, thereby preventing any furtheroperation of the operating magnets.

Now as soon as the relay 38 closes its springs 14 and 15, a circuit isthereby established for the H through the wound relay operate at thistime line relay 41 of the connector windings of the differentially 42.The relay 42 does not as the magnetic fields set up by the current flowin its two windings neutralize each other. relays 41 and 42 through theThe circuit for extends from battery upper winding of relay 41.

springs 43 and 44, upper winding of relay 42, wiper 22, repeating coisprings 14, winding 39 of the l, springs 11, lower winding of relay12,;resistance 13, which may be approximately ;200 ohms, winding ofrepeating coil, springs 15, wiper 23, winding of relay :42, springs and46, and lower winding of relay 41 to ground. .The relay 12.of selector Edoes not energize at this time as the current in its two windings flowsin opposite directions. The line relay 41, uponenergizing, closes thecircuit of slow relay 52 through the springs 53 and 54, which relay,upon energizing, connects ground to the release trunk through springs4'1 .to render the:switeh busy to other calls and also to supply anadditlonal ground to the holdingcircuit of relay 38 (Fig. 1). This.samepa'ir of springs also closes a circuit for the up er windingof theslow. acting ring cut-ofi relay-48, said circuit extending from ,groundthrough springs 47, resistance 49, 1 wiper of the frequency selectingswitch and upper winding of relay 48 to battery, The, springs 55 closedat this time have -no .efi'ect, while the closure of the springs 56 and57. preparesa circuit for the motor magnet 58 at one point. The relay48, upon energizing, attracts its armature to closea number of springcontacts, only one, however,.hav.ing any etiect at thistime, that beingthe springs. 59 and 60 which operate to;close a second contact pointin.the circuit of .magnet 58; Now when the operator sendsout the 'seconddigit of the called number, the line-relay 5.0f selector-E will beoperated-as in the; previous digit to attract and retract its armaturesa predetermined number of times. The closure of springs 8 and 21hasnoeilect at this time due to the springs 61 being held open by relay38. The opening-and closing of springs 11, however, opens and closes thecircuit, previously traced, ofthe line relay'4l of the connector H. Therelayi41 each time it retractsrits armature closes-a circuit for themotormagnet 58 extending-from ground through the springs 53 and 62,springs 56 and 57, oilnormalsprings63 and 64, springs-59 and 60, springs65, and magnet 58 to battery. The magnet 58 operates in response to thisdigit tostep the wipers 50 and 51 to a certain set of contacts, therebyselecting the desired frequency of ringingcurrent to which the wantedsubscribers bell is tuned. It will be seen that, as soon as the wiper 50leaves its first or normal position, the previously traced circuit forthe upper winding of relay 48 is opened. This relay is maintained inenergized position however during the operation of magnet 58 by theoperation of the springs 66 which intermittently applies ground to saidcircuit. The relay 48 being slow acting will therefore maintain itsarmatures attracted until the magnet 58 ceases its operation, at whichtime the relay 48 will deenergize and open the initial enen giz ngcircuit of the magnet 58, which can not again 1 he closed because iof,the wiper.;50 1

being in,.advanced pqsitian; .;Assuming1;the

second .digit to have-been; 3 .thennthe wipers- 50 and 51 will 1 be leftstanding .=in ,thind; position with the generator fRrconnected to.

impulses of this digit, again operates tc open and closeatheisprings53i-and=62.- :The

relay -48 having fallen .back, the vertical.

magnet will be.-opera/ted in. placeof the motor magnet 58. The circuit;of the ver; tical magnet extends: from ground through springs 53 and 62;springs 56 and 57,-;spr-ings 63 and 64, springs 59 and 68, gslow delay69, and verticalmagnet 70 toibattery. The vertical. magnet will operateda' number of time S"t0;SteP- thG'Wip6IS 71,. 72, and 7-3to a. a group orlevel of .itrunk; lines .in which the terminalsof the desired line-arelocated. Uponithe first vertical;.-step of :the:-wipers, the 'ofi'mormahsprings 63 and -64-are opened and-spring 63 comesinto contact withspring 74, .andthesprings 7'5 arefelosedu 'A'lthough the circuit. forthe-vertical magnet? is opened by. the :springs 63 and; 64p amew-.circhit. has been prepared in the; mean-while by the-toperation of.1 relay 69, 5 which I circuit-2 extends from ground through-springs-.53.-:and 62-; springs 56 and 57 springs-63\and 74, springs 76and 77 ,and =over thepreviously traced circuit through theverticalmagnet. It may be noted ,that. --'Fthe slow relay :52 *remai-nsenergizedduringthe entire operation of: the line relaywregardless of themomentary-dc"- energi'zations thereof, and that the relay '69 remainsenergized'constantly :during. the vertical :series of impulses. Now when:the relay 41 comes 'to rest-energized zafterz't-he impulses to theverticalmagnehpease the relay-69 will deenergize, opening, its owncircuit at the springs 76 .and77,;'and closing, atthe. springs-76 and78,.a point intheci-rcuit of the rotary *magnet 79' and'also of the slowrelay -80. Now when the= line-relay 41 is-again-roperat'e'd in-res-ponseto the :fourth or last digit, through the -m'edium of the line relay-5of -selector E, the rotary magnet 79 is operated to rotate the wipers71, 72. and 73 to the terminals of the desired line, The "circuitoff-Lthe rotary magnet extends from ground through springs 53 and -62.springs 56' and 57,-springs63 and74,-springs 76 and78,springs--81,springs-82 and 83, and rotary magnet 79-to battery. Abranch of this circuit extends from. the springs 81 through theslow'r'elay- 80 to battery so that relay 8O and'imagnet 79- areenergized in multiple. Thetrelay80 energizes: upon the first impulsandc'loses thesprings 84, thereby short circuiting the springs-:81 of;relay 85 and maintaining the circuit of itself and magnet'7 9=closedfirrespective of the conditionlof relay 85 during thisscries of impulses.Another result of the energization of theslow relay 80-isto close apoint in the circuit of the busy or test relay 85, at

the springs 8 6and 87. The relay-80, being fr0m,as shown, the' privatecontact willbe groundedw- Before the springs"86'-and; 87 arepened,'-therefore,- a circuit willbe completed' for the busy re'lay 85,-extending' f-from ground to the wiper '73,springs 86 and 87,

relay 85, springs 65. and'm'agnet58 toibat'--' tery. The relay"i"58'will-not energize in series with relay 8'5' w hich isof high.-resistance. The relay' 85, *howeve'r, energizes to close a locking'cir'c'uit for itself whi'ch -is closed as soon as relay' '80 falls back'and extends through springs 87 and; 99, springs 96 and 1 91," springs90 and 8 9,-"-and springs 47 to groundWRelay 85 also opens-theinitialenergizing cirbuitfi'for the rotary magnet and relay '80 atsprings8l,closes a shunt or short circuit'about the lower winding ofslow relay 42 at springs 97,"and* connects the secondary winding' of thebusy machine M with the lower talking conductor, thereby giving theoperator-a 'busy signal. I r

The short circuit which'was thus established about thelower winding'ofrelay 42 causes said relay, whose windings are differential, tobeenergized, thereby switch ing the locking circuit of the busy relay 85to-the wiper 73. This" new circuit extends from ground at wiper 73,springs 98 and 90, springs 91 and 96, springs 99 and 87. relay 85,springs 65. and magnet 58 to battery. It will be seen, therefore. thatthe relay 85, instead of being permanently-locked, remains energizedonly as long as the called line is in-use and until the ground isremoved from the private contact thereof.

As soon as the ground disappears from the private wiper 73, the relay 85will de energize and restore its springs to normal. The shunt'beingremoved from the winding of relay 42 by the opening of springs 97, saidrelay will deenergize after a brief interval and close one point in thecircuit of relay 88. The circuit for relay 88 is now complete andextends from ground through springs 47, springs 89 and 90, springs 91and 92, lower Winding of relay 88, springs 93 and 86, private wiper 73,relay 94 of line switch C, and magnet 95 to battery. Relays 88 and 94energize over this circuit, relay 94 being mechanically adjusted so asto attract its armatures only half way when the line relay 100 is notenergized, willtlierefore operate to disconnect the relay 100 and groundfrom the, called line. Relay 88, upon energizing, closes'a lockingcircuit for its upper winding through springs 101, opens the (ll'taiit'of magnet- 58, and places a direct ground on the wiper 73 to maintainthe alled line busy and also to short circuit its own lower winding.Another result of the energization of'relay 88 is the closure of thesprings 102 and 103', thereby connecting ringing current to thecalledline. The ringing circuit extends from battery through the upperwinding'ofrelay 48, springs 104 and 105, springs 102,-wiper 71, to andthrough the ringer of substation A, and back through wiper 72, springs103, springs 106 and 107, to spring 108.'- The spring 108 is controlledbythe common interrupter relay 109 to connect the above t aced ringingcircuit alternatelyito battery and to the generator B through wiper 51',which now stands in third positionJf-Asdong as the receiver-of thecalled station remains on the hook, the ringer thereat w-ill be operatedintermittently and the 'relay'48 will remain deenergized beingnomre'sponsive to alternating current. When the receiver is removed inresponse to the signal, a direct current circuit will be established forsaid relay 48 which will immediately energize to disconnect the rin inglead from the'circuit of the called line y opening'the springs 107 and106 and to connect the talking circuit from the condensers 110 and 111to the Wipers 71 and 72. The energization of relay 48 connects theground from springs 112 through springs 113 to close a locking circuitfor its own lower winding and also connects said ground to the lowerwinding of back bridge relay 114. The springs 105 and 106, upon engagingtheir front contacts, close a circuit for the back bridge relay 114,extending from ground through springs 112, springs 113, lower winding ofrelay 114, front contact of spring 106, springs 103, wiper 72, throughthe talking equipment of substation A, and back through wiper 71,springs 102, spring 105 and its front contact, and upper winding ofrelay 114 to battery. The relay 114 energizes over this circuit andoperates the springs 115 and 116 and the associated contacts to reversethe connections of line relay 41 to the talking circuit, and to shortcircuit the windings of relay 42. This causes a reversal of current inthe talking circuit to the lower winding of the elcctro-polarized relay12 of the selector E. The relay 12, now having both windings assistingeach other, operates to close the circuit of relay 120 at springs 121.The relay 120, upon energizing, opens the circuit of relay 122 atsprings 123 and closes a new circuit for the lower winding of relay 12at springs 124, and replaces the relay 6 directly in the operatingcircuit-of the operator place of-relay-5 which nowdenerg'izes: Theclosure? of springs 125 at this time closesfthe series circuit for asupervisory signalat the operators cord circuittocontrol theusual-operato'rs'signal to notify 'theoperates-that the called man hasanswered and alsoshbrt circuits the relay 122; The 11'? are also closedthe relay 114 toimaintainithe connectingrelay-"88 energiz'ed'in case thcalling nian should hang-up firsttoimairi tain-the connectoroperated-,-

thle i 118 are opened by relay-114 tof-inai'nt'ain t a circuit ofrelease magnet 119*bp n nu 1-rhe calledman hangsup; i

Conversation may now proceedover' the heavyconduc'tors shown in thedrawing and when the conversation is comfp1eted,jthe-con; ne'ctor may berel'e'ased by' either the hpe'ra tor or called'man that is, bytheopprator r a l p r y-d pad wrfin which" one disconnects last, while"selec\- to'r E is restored-{by the operatorlonly Should the callingsubscriber hang Qupifijrst, the operator iwill; remove the plug; fromjack' XI and thereby open thegcir'cuitjolf the relay 6 atthe jack. rel ay' fi on denergiz'ing, closes an energi'zing'jcircuit for the releasefrn'agnet {272 and.' opensx the holding circuits ofrelays 38and' 12.f'The selector Ei s thereupon releasedan in re leasing opens the circuitofline relay '41 of connector Hi The relay 41,- u on deenergizing, opensthe circuitof rel'ay 152. The deenergization of these two relaysprepares a circuit for the-release magnetl19 which is held open atsprings 11 8 '-of back bridge relayll. The connector H'ispre: ventedfrombeing seized by another? selec-i tor switch, while it is maintained inan. operated position by the calldsubscriber having his receiver ofl theswitchrhook, by:

a ground potential onthe testvco ntact of,

the associatedtrnnk line, this -ground:being supplied from thesprings120 on the connecting relay 88. As soon as the calledsubscriberhangs. up his receiver, the switch will be released in the. usual mannerby therelease of relay 114 and the-subsequent operation of releasemagnet119. Should, the ca led subscriber have hung up his re ceiverfirst. the-relay 114 would deenergize to close the springs 118 and to-againoperate the supervisory signal in theopera-v tors cord'circuit bymeans of relays 12 and 120,01 elector E, after which the operator wouldwithdraw the plugto deenergize rela 41 and release the switches intheusual manner.

hen the operator is calling a subscriber in the manner pointed out, itisoften neces-- same subscriber. In this case,jthei operator will "press5 the usual ringing iiey to connect enerator out 1' over her, cordcircuit and firmgs' the-Xvih'dihgs of a special, tuned relay .122,(Fig'. "Therelayf122 willfnot be short: circui-te'dWby 3 springs; "125at this time, as relay 191) "will" "denergized whenthe called"subscriber haln gs The relay 29, uses energizing; fclos'es thesprings126- to short circuit an's min-ding we e iaysaaandai i 2- ams-s arecircuit extends ground .thr ough springs :26, winding 40 of 'the' "reeaafi 6011;; sprir'igs 15, wiper 23, lower winding of"relay"42; springs45" and and" lower l'windingj of may 4 1""to',f= round. Therelay 12being afaeremiarwni"ene gi e atthis am; to ges r t? 1 2; im 'p t ntirbwh s ate n i i 1 r i u i f f ee e ar 4 ll? hem. are d' rgiz' eeaii i e h"sfiiiis r e es s me; PQ T Lth F i dt i; af e his se fo b d a a eri aeaerehss heea 1 1g isngwerea ts disc ne'ct me singing circuit ai -a{conversation agiafwt ke: gla'cejffb shownf. q I a I It? Q-beiseentherefore I have provided" a very efliqi ent system of zen-rag" 'a'party line suhiscriberf fro i n an operator in which thirr qusncygasji'edi i eel-(s r ams hire the lflllr'ie 'selcted so thaijii "a? sysrem;irifiw vhi ch the tease-aids iscut' 'thiiou 'h af e a Busy: biljdffiiief i uremia qa f$ i s1iifi t" i 1' be' ig a ifi f flii at riii iIrt i'rI fi n 'y. th .1 1 ata i a d. n? wh ch l hous i an mi fusedsignal, such subscifibelf, the lie f t s' m r; t any time tet Q a d s'ubItib rsr eH Havinghfully ascertained and described my invention, what' lclaim to be new, and, e'sirefto',lrave"protected 2 Letters Patent willbe'pointedb ut inthe appendedcl'aims.

"What Iclaim as my invention is:

1. Inna telephone system,' a, p lurality'of generators, eachsupplyingcurrent' of different frequency a party line, aQplurality ofstations on said party line eachlhaying. a: signal "responsive tocurrentfrom one of said generators, a switch forconnecting with saidparty .line. another switch' individual a kin eto said. firstswit chbut:having: a. separate.

2.1 In a, telephone: system, a. plurality of, sources ;ofalternatingcurrent, .eachr supply.

ing current of difli'elent frequency, a line,

an automatic switch having vertical and rotary motion for connectingwith said line, an auxiliary. switch associated with said automaticswitch and operable independently thereof for.sclecting; one of saidsources .of current, v means for deliyering a plurality of series ofimpulses tosaid automatic switch, an'd'means. whereby the first, of saidseries of impulses operates said auxiliary switch to select a source ofcurrent and the others of said series of impulses cause said automaticswitch to move in a vertical. and.rotary.m0- tion toconnect 'saidselected sourcezof current to said line. t ,1.

3,111 a;.t elephone'system, a,line,- an.auto-, matic sw'itch,-',aplurality fsources of ring current, an auxiliary, switchassociated withsaid automatic switch and operable independently thereof for selectingone of said osou'rces, means for. sending a plurality of. series jofimpnlses to said automatic switch ,for first; operating said .auxiliaryswitch, toselect one of,said, sources and for thereafter operatingsaidautomatic switch in response to a plurality of .series, of pulses tolfind said line ,andlconnectfsaid .se;.

lected source of ringingcurrentxtherew itk i M v 4, In atelephonesystem, .a ,pa,I ty- 'l-ine, an operator s cord circuit, an,automatic switch, a; plurality or sources. of- ..ringing. current, aplurality o f; stations on said lineeachaesponsive to cur'rent fromonly, one of said sources of curren t,'means for makingsaid called linebusy, means controlled by said operator foroperating saidsWitch to;first select one of said sources of currentand then connect saidautomatic switch with, said, line while busy, means controlled by' ,thebusy condition of said linel for preyenting the establishment of a'talki'ng connection with said party line. means for automaticallyestablishing-a talking connection withsaid line when it is again idle,and means controlled by the idle condition, of said line for connectingsaid selected sourceof ringing current therewith. 7 p

5. In a telephone system, a party line, an operators cord circuit, anautomaticswitch, a plurality of sources of ringing current, a pluralityof. stations on saidline each, re sponsive to current from only one ofsaid sources .of current, means for making said called line busy, meanscontrolled by said operator for operating said switch to first selectone of said sources of current and then connect saidautomatic switchwith said line while busy, means controlled by the busy condition ofsaid line for preventing the establishment of a talking connection withsaid party line, "means for automatically establishing a talkingconnection with said line when it is again idle, means controlled by theidle condition of said line for connecting said selected source ofringing'ourrent therewith, and means controlled by a called one of saidstations for disconnecting said source of of current and establishing'atalking circuit with said operator.

. 6. In .a telephone system, an automatic switch,, a line relay for saidswitch, means for-operating said linerelay in response to a plurality ofthe digits of a called number, an auxiliary switch associated with saidantomatic switch, an operating magnet for said auxiliary switch, anoperating magnet for said automatic switch, means whereby the operationof said line relay in response to said digits, first operates only theoperating magnet of said auxiliary switch, and thereafter operates theoperating. magnet of said automatic switch.

Q17 .In a .telephone system, an automatic switch,a .line: relay for saidswitch, a called line a ,plura l ity of sources of ringingcurrent, anauxiliary switch for selecting one of said sources, a pair of operatingmagnets for said automatic switch, an operating magnet forsaid'wanxiliary switch, means for operatingthe llinemelay' of said switch inresponse mpn adigit'gofa caHednumber to operate the operating. magnetof, said auxiliary switch to selectone'of' said sources of ringingcurlien h'and means for thereafter operating s'a idline relay inresponseto a plurality of digits of the calle'd number to operate said i'rofoperating magnets to connect with said jc'alled line.

8. In a telephone system, an automatic switch, a line relay-for saidswitch, a called line, a plurality ofsourcesof ringing current,ananiiiliar'y switch for selecting one of said sources, a pairvofoperating magnets for' said automatic switch, an operating niagnet forsaidauxiliary switch, means for operating the line relay of said switchin response to onedigitof a called number to operate the operatingmagnet of said aux iliaryswitchto, select one of said sources of ringingcurrent, and means for thereafter operating said line relay in responseto a plurality. of digits of the called number to operate said pair ofoperating magnets t find said called line and connect-the selectedsource of ringing current thereto.

9. In atelephone system, an automatic switch a line leading to saidswitch and individual thereto, aparty line accessible to said swit hmeans for sending a plurality of series of impulses over said first lineto said switch, five sources of ringing current, a selecting deviceandmeans for operating it responsive to the first series of impulses toselect any one of said sources of current without operating said switch.and means responsive to the succeeding se ies of impulses for operatingthe s itch to connect with the said party line and signal the stationthereon by means of the selected source of current.

10. In a telephone system. an automatic switch having a vertical androtar y motion, a line leading to said switch and itgdividual thereto, aparty line accessible' to said switch, means for sending -a gltrrali tyo' fseries of impulses over sa'it'l firstl i ne to said 3 switch, aplurality of sources wrin ing-enemas a step by step switch responsiveto""rhe "first series of impulses to select one of said sources ofcurrent, amagnet responsive only to the nextseries ofimpulses-'tooperate saidswitcli vertically to' select the-group of"lilies-" in which the party line is located, and a second magnetresponsive to the lastflseries of impulses to rotate the swit clr to'thedesired partyline and signal the station thereon by means of theselected source of current.

11. In a telephone system, an operators position, an automatic switch,means for connecting said switch'wit-h said operators position, anauxiliary switch individual to said automatic switch. a plurality ofsources of ringing current, a line relay in said automatic switch, meansfor operating said line relay to cause said auxiliary switch to select asource of ringing current in response to the first digit of a callednumber, means for operating said line relay thereafter responsive to aplurality of other digits to cause said automatic switch to establishconnection with the desired line, means for preventing the establishmentof a. talking connection with said line and the application of saidselected ringing current thereto if busy, and means for establishingsaid talking circuit when the said line becomes idle.

12. In a telephone system, an automatic switch. a line relay for saidswitch, means for operating said line relay in response to a pluralityof digits of a called number, an auxiliary switch individual to saidautomatic switch. a differential relay in said automatic switch, anoperating magnet for said auxiliary switch. an operating magnet for saidautomatic switch, means whereby the operation of said line relay inresponse to said digits first operates the operating magnet of saidauxiliary switch and thereafter operates the operating magnet of saidautomatic switch to complete a connection to a called line, and meansmade operative if said line is busy for energizing said differentialrelay.

13. In a telephone system, a plurality of sources of signalling current,each of said. sou ces supplying signalling current of a differentfrequency, a line, an automatic switch for connecting with said line,means for sending e. plurality of series of impulses to said automaticswitch, a step by step switch individual to said automatic switch andoperable independently thereof responsive to the first of said series ofimpulses for selecting one of said sources of current. and means wherebythe remaining series of impulses ope ate said automatic switch in twoplanes toconnect said source of current te-saidline 14'. Ina-telephonesystem, ali ne, an automatic switch, a plurality of sources o' f'ringing- -curren-t, means for se'nding a"plurality of; series ofimpulses 1 to *s'aidj automatic switch eorres osding w digits ina'fc'i-illed number, an" auxilialy-s'tep by Step switch associated withsaid automatic switjliand operable independently thereof responsive tothe-first digit ofsaid plur' lity foi' se'l'e'c'ting one ofsaidseliirces,fan'tlfrneensf for o'p-' erat-ing' said ai'i'tomaticswitch'in 5 resp ase te the tflnrality bf' series-of impulses eer espo'iieling tothe re/massin "digits of (said plurality to' s ltt saidline and doilnecti said selected source of ringing current thereto.

15. A telephone system including a called and a calling subscribersline, a side-switchless connector switch, means for connecting saidconnector switch to said called subscribers line, ringing currentgenerators, a frequency selector for said connector switch,subscriber-controlled means for operating said frequency selector toselect one of said ringing current generators, automatic means forintermittently applying ringing current from said selected generator tothe called subscribers line, and subscriber-controlled means fordisconnecting the selected generator from the called line during aringing period if the called subscriber answers during a ringinginterval.

16. A telephone system including a calling and a called subscribersline. a sideswitchless connector switch adapted to connected to thecalling subscribers line. ringing current generators, a frequencyselector for said connector switch, subscribercontrolled means foractuating said connector switch and said frequency generator over thetwo sides of the calling subscribers line in series for extending theconnection to the calling subscribers line and for selectins: one ofsaid ringing current generators, automatic means for intermittentlyapplying ringing current from the selected generator to the calledsubscribers line. and means responsive to the removal of the receiver atthe called substation for instantly disconnecting or for preventing areapplication of ringing current to the called subscribers linedepending upon whether the called subscriber responds during a ringinginterval or a silent interval.

17. A frequency selecting connector comprising a connector switch and afrequency selector switch individual thereto, an operat ing magnet ineach switch. a line relay in said connector switch. an operating circuitnormally leading from the line relay to the connector switch magnet. andmeans effective when the connector is taken for use for transferringsaid circuit from the connector switch magnet to the frequency selectormagnet and responsive to a series of impulses transmitted over saidcircuit for transferring the same back to said connector switch magnet.

18. A connector as set forth in claim 17 in which the ring cut-ofi'relay constitutes the means for transferring the operating cir cuit fromone magnet to the other as specified.

19. In a telephone system, party lines, an automatic switch having avertical and rotary motion for selectm a party line, a trunk lineleading to sai switch and individual thereto, means for sending aplurality of series of impulses over said truni; line to said switch, anauxiliary switch individual to said automatic switch for selecting aparty on any selected party line, a magnet for operating said auxiliaryswitch, a first and a second ma et for operating said automatic switchin its vertical and ro tary motions, respectively, and means foroperating said auxiliary switch magnet responsive to the first of saidseries of impulses and for operating said first and second automaticswitch magnets responsive to the next two of said series of impulses,respectively.

Signed by me at Chicago, Cook County, Illinois, this 5th day ofFebruary, 1918.

EMIL J ACOBSEN.

